Many conventional modular blocks assembled for use in water all pose problems of sea state capability when the sea is choppy, particularly when these structures are not placed in the shelter of a harbor. Many of these structures consist of modular floating blocks with the anchoring or securing of the structures brought about by horizontal bars provided with lugs which cooperate with the lugs of the blocks in such a way that they are run through by keys, these bars being arranged on the side of said structures. This method of securing the floating structures thus executed does not prove satisfactory with use.